Capacity in the interim nuclear storage facility is sufficient for longer nuclear power plant lifetimes

To date, a total of 85 Castor casks weighing several tons containing spent, highly radioactive fuel rods from Swiss nuclear power plants have been stored in a protected hall in the central interim storage facility (Zwilag). This means that 42.5 percent of the storage capacity has been used up, according to a request from the media office of the energy company Axpo.

The containers give off heat - and therefore cannot yet be disposed of, even if a deep geological repository were available. All spent fuel rods from the Mühleberg BE nuclear power plant, which is currently being dismantled, have been in Würenlingen since September 2023.

Enough space for spent nuclear fuel rods

An analysis by the National Cooperative for the Disposal of Radioactive Waste (Nagra) shows that there is sufficient capacity in the storage facility for the interim storage of all waste, Axpo stated.

A possible optimization of the storage area could create additional capacity for highly radioactive waste. This would allow the waste to be stored according to plan, in compliance with safety regulations and in accordance with quality standards, even if the nuclear power plants were to remain in operation for a longer period of time.

The storage capacity for medium and low-level radioactive waste from medicine, research and industry is currently around 22 percent full. Some of this waste was previously thermally decomposed or melted in a plasma furnace at temperatures of up to 20,000 degrees Celsius. These materials are then sealed in drums suitable for final disposal.

The operators of the interim storage facility are the joint stock companies of the Swiss nuclear power plants. Operating costs amounted to CHF 32.6 million in 2023. The number of employees at the end of 2024 was 102.

Compensation payments for the region

The choice of site for the interim storage facility was preceded by a lengthy discussion in the lower Aare valley in the 1990s. In a referendum in November 1989, the voters of Würenlingen approved a contract with the repository operator - by 707 votes to 662, with a turnout of 71.6 percent. This confirmed the decision of the municipal assembly.

Specifically, it concerned a contract between the municipality and Zwilag. It stipulated how Würenlingen's favorable location would be compensated financially: The operator now pays 1.8 million Swiss francs per year to Würenlingen and the four surrounding municipalities - until 2074.

At 1.3 million Swiss francs, the local municipality receives the largest share. In addition, there are share taxes and compensation payments from the Beznau and Leibstadt nuclear power plants, which are also located in the region. The nuclear plants are the most important employer in the region.